Lapping apparatus



July 28, 1942. D. WALLACE 229L LAPPIN G APPARATUS V.

Filed March 24, 1937 11v VENTbR, gym id'- Mild w. v

A TTORNE rs.

Patented July 28,- 1942 in STATES; ATEN'T OFFICE 'LAPPING APPARATUS Y DavidA. Wallace, Detroit, Mich, assignor to Chrysler Corporation, Highland Park, Mich, a

corporation of Delaware Application March 24, 1937, Serial No. 132,688

9 Claims.

. relative movement of this character between a lapping element anda surface being lapped which is the resultant of so many components that even during repeated application of the lapping element to the work surface, no isolated area or particle of the lapping element 'willbe repeatedly applied to the same increment of area of the work.

A still further object of the invention is to provide relative movement between a lapping element and a piece of work which is a resultant of simultaneous relative rotating and revolving actions between the work and the lapping element.

Other objects of the invention are to provide in lapping apparatus of this character, means for rotating a lapping element about one axis and revolving the same about another axis during application of the element to a surface of a piece of work; to provide a work support by which a piece of work is rotated about one axis and revolved about another axis during application thereto of a simultaneously rotating and revolving lapping element; and to provide a lapping tool for operating upon work supported by, and moving in accordance with the movements of a work support of the foregoing character, which simultaneously rotates and reciprocates the lapping element while the latter is contacted with the work.

Additional objects of the invention are to provide means in lapping apparatus of this character for simultaneously rotating about one axis accommodates rotation of the pieces of work about certain axes thereof; and to provide meansfor drivingly operating the opposed lapping element in respectively opposite directions so as to promote uniform turning of the pieces of work 7 about their respective axes.

Another object of the invention is to provide an improved lapping member having un-uniformily shaped lapping surfaces yieldably mounted in a substantially common plane and assymmetrically arranged in spaced relationship so as to present interrupted and irregular parting lines between the surfaces.

' Illustrative embodiments of the invention are shown in the accompanying drawing, in which: I

Fig. 1 is a front elevational view, partly in section, of a lapping machine embodying the invention.

Fig. 2 is a fragmentary, horizontal, sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a fragmentary, vertical, sectional view taken on the line 3- -3 of Fig. 2.

Fig. 4 is a fragmentary, vertical, sectional view of a lapping machine embodying an additional form of the invention.

In the form of the invention illustrated in Figs. 1 to 3, inclusive, of the drawing, the improved lapping machine comprises a base structure, generally designated by the numeral 10, having a lower horizontal bed portion 1 l and an upstanding verticalv back portion I2. Formed in the bed portion H is a cylindrical bore l3 having counterbored recesses M at its opposite extremity. A tubular journal member l.5 is rotatively supported in the cylindrical bore I3 by bearings I6 disposed in the recesses 14. Each bearing l6 comprises inner and outer bearing rings I1 and I8, respectively, between which is disposed a series of ball bearings IS. The tubular journal member i5 is provided at its upper end with a radial flange 20 which is seated upon the upper edge portion of the inner bearing ring H, as 11- lustrated in Fig. 1. portion of the journal member I5 is a counterbore 2| in which a bushing 22 is disposed. The lower end portion of the journal i5 is a suitable counterbore, as illustrated at 23, for the reception of a roller bearing unit 24, which is removably held in the lower end portion of the journal member I5 by a threaded plug 25. v A; combined work supporting and lapping element 26 having a spindle portion 21 journalled in the bushing 22 and bearing unit 24 is rotatably mounted in the journal member IS, the bushing 22 and bearing unit'24 being so constructed and arranged as to bring the rotative Formed in the upper end axis of the spindle 21 into eccentric relationship withrespect to the rotative 'axis of the Journal member l5. This may be accomplished by suitable bushing and bearing construction or by forming the counterbores 2i and 23 of the journal member II eccentric with respect to the axis of rotation of the latter.- The lower'end portion of the spindle 21 is provided with a reduced end portion 28 on which a pulley 29 is non-rotatably fixed. A'coilar ll having a belt groove 3| therein is non-rotatably flxed on the lower end portion of the :Ioumal member I which extends below the lower extremity of the bed portion ll of the base structure. The pulley 29 and collar 3. are drivingly connected by belts I2 and 33. to driving pulleys 34 and 25 mounted on a shaft II of an electric motor 31, orother suitable driving meanscarried by the base structure Ill. Belt tensioning members 28 and is having idler wheels "and ll on their free end portions, re-

spectively, are provided for taking up the slack in the beltg l2 and I3. Thecombined lapping truding lug it in which is threaded an adjustable set screw .1 that may be selectively fixed in a predetermined position by a lock nut ll.

' The head oi the set screw 81 is adapted to register with 2. lug '2 formed integral on the carriaBe 42 in order to limit downward movement of the carriage and predetermine the spaced relation'ship between the discs 42 and N of the lapping tools 2! and 52, respectively. p

The vertically reciprocable carriage 43 is counterbalanced, in order to facilitate convenient movement the f to, accommodate the placemerit of work between the lapping tools I2 and 28 by the provision of a cable which is atpulleys l2 and 13.

and work supporting element comprises a disc Mounted in the counterbore recesses 41 are roller bearing units 48 in which a tubular journal member I! is rotatably mounted. The lower end portion of the tubular Journal member 49 is'counterbored and provided with a bushing I0 and the upper end portion of the tubular journal 4! issimilarly provided with a counterbore in which is mounted a roller bearing member II.

A lapping tool, generally designated by the numeral 52, is rotatably mounted on the block I and has a spindle portion 53 journalled in the bushing 50 and roller bearing unit 5|. Provided on the lower extremity of the spindle portion 53 is a disc 54 which is, disposed in opposing relationship with respect to the disc 42 of the combined work support and lapping tool 26. The bushing 50 and bearing unit 5| are preferably so constructed and arranged as to bring the axis of rotation of the spindle 53 into eccentric relationship with respecttothe axis of rotation of the journal member 49, as illustrated at 54 in Fig. 1. The upper end portion of the tubular Journal member I! and spindle 53 extend beyond the corresponding end portion of the block I, and the spindle 53 has a reduced end portion 55 which extends beyond the upper end'portion of the journal member 49. Non-rotatably secured to the reduced end portion 55 of the' spindle I} is'a pulley 56. 'A collar i1 having a pulley groove 58 therein is non-rotatably keyed in the external end portion of the journal member 49. Thepulleys 68 and collar 5'! are drivingly connected by belts l9 and I, with driving pulleys Cl and 62, respectively, mounted on a shaft 03 Ma motor. The motor 04 is carried by an extension I of the carriage 43, as illustrated in Fig. 1. Provided on the back portion l2 of the base structure II is a forwardly protachedto the carriage 42 at H and extended over The free end of the cable is provided with asupport I4, upon which weights Il may be placed. In practice, a sufficient number of weights II are placed on the support 14 to substantially accurately balance the mass of the carriage and all parts of the apparatus supported thereby. After this is accomplished, a selected number of weights I. may be mounted on the upper extremity of the carriage 43 in order to accurately predetermine the pressure with a which the lapping tool I2 is applied to the work,

A single piece of work comprising a disc-shaped or other shaped structure (not shown) may be disposed between the lapping tool 26 and 52, on the adjacent sides of which are provided lapping elements 11 and 18, respectively, which will 'be hereinafter more clearly described. During operation of the opposed lapping tools by their respective motors 31 and 64, both sides of the work, which may be suitably held, if desired, against movement relative to the base structure II by any suitable clamping means, are simultaneously operated upon. The combined rotating and revolving actions of both of the lapping tools 26 and 52, which may be caused to occur in the same or in opposite directions depending upon thedirection of drive of the motors fl and It, produces a movement of the lapping surfaces relative to the work which is a resultant of the component revolving and rotating movement resulting from the eccentric relationship of the axis of the spindle of the lapping tools with respect to the rotating Journal members in which they are mounted. By virtue of this action, the repeated application of localized areas of lapping surface to the same increment of area ofthe-surface of. the work is eflectively guarded against and the lapping surface is so moved with respect to the work surface as to emciently remove even microscopic machine-formed grooves and ridges from the surface of the work without forming scratches thereon by'repeated retracing of localized hard par- "ticlesof the lapping surface over the same increment of the area of the work.

In the form of the invention illustrated in Pigs. in 0 8, inclusive, the lapping machine is equipped lapping of the cylindrical parts of a lurali articles, D W of such as the stems of valves of the type commonly used in internal combustion engines. The valves 19 are preferably disposed in a radial arrangement, as illustrated in Fig. 2, with their stem portions interposed between the lapping elements I1 and II of the lapping tools 28 and '2, respectively. A spider ll comprising a disc having radial slots ll therein for accommodating the valve stems, is preferably located between the lapping elements I1 and II and anchored against movement relative to the base structure I. by I apparatus for accommodating simultaneous portion 42 of the tool.

pins 82 mounted on the latter and received in apertures 84 of ears'85 formed integral with the spider 80. By disposing the stem portions of the valves 19 in the slots 8|, the valves are held against displacement with respect to each other during the lapping operation while they are.free to rotate about their longitudinal axes. Radially outward movement of the valves from between the lapping elements H and 18 is'prevented by a track structure 85 mounted on the bed H and provided with spaced flanges 81 and 88 between which the head portions of the valves are received.

During simultaneous lapping of a plurality of articles in the foregoing manner, the direction of drive of the motors 3i and 64 is preferably predetermined to cause the lapping elements ll and It to rotate'in respectively opposite directions in order to promote rotation of the valves relative to their longitudinal axes, thereby introducing a further component of relative movement between the work and the lapping element.

The lapping elements ll and l8 may comprise integral ring-shaped stones of either artificial compositions or natural stone which may be secured in a conventional manner to the disc portions 42 and d, respectively, of the lapping tools. The lapping element illustrated comprises a plurality of differently shaped pieces of lapping material 89 which are rigidly bonded to a layer of rubber 90 provided on the side face of the disc The rubber layer 9!! may be of a hard ebonite-like composition or it may be relatively soft and yieldable in order to provide a a yieldable backing for the pieces of lapping material 89. By virtue of this construction, a multiplicity of discontinuous and irregular parting lines are provided between the particles of lapping material so that at no instance is a substantial portion of the length of the stems of the valves subjected to the action of a continuous edge portion of a particle of lapping material. Relative spacing of the particles of lapping material from each other, illustrated in Fig. 2, provides space accommodations for the fine powder-like substance which accumulates on lapping members and which comprises a combination of particles of the work and particles of the lapping material.

During operation of the foregoing lapping machine, either the lapping tool 26 or the lapping tool 52 may be allowed to remain at rest while the otherlapping tool is rotated and revolved in the foregoing manner. If desired, one of the lapping tools may be subjected to a combined rotating and revolving action while the other is only revolved, or only rotated. This may be accomplished by employing all the driving belts 32, 33, 59 and fill or by removing selected belts, as desired.

In Fig. 4 of the drawing is illustrated a lapping machine similar to that shown in Fig. 1 which includes opposed, rotatable and revolvable lapping members that are laterally, bodily ofiset a distance'substantially equal to the radius thereof.

Although the driving mechanism for the lapping members of the form of the invention shown in Fig. 4 is. not included in this fragmentary figure, it is apparent that the structure of this form is so similar to that shown in Fig. 1 that the same driving apparatus may be employed to rotate and revolve the lapping membersin any of the manners described in the discussion of the structures of the other figures. Corresponding parts of the structure shown in Figs. 1 and 4 are designated by identical numerals.

Disposed between the offset lapping tools 52 and 28,. of the lapping machine shown in Fig. 4, is a work spacing and conveying spider I50, similar to the spider 80 of Fig. 1, having substantially radially extending work receiving slots I5! therein. The spider I50 is rotatably supported by a stem portion I52 secured to, or formed integral with its central portion, which is journalled in a,sup-.

port 953. The axis of the stem portion I52 may be concentric with the center of the lapping tool disc 42 or otherwise so suitably spacedtherefrom as to bring a substantial portion of the spider between the opposed portions of the lapping elementsl'l and it of the lapping tools. The slots 15! of those portions of the spider which do not extend between the lapping surfaces El and II may be progressively loaded with pieces of work, illustrated at Mid, and the spider may be progressively turned either manually, mechanically or automatically by driving mechanism (not shown) in either a continuous or intermittent manner. Lapped work can be removed as it is carried outwardly by the spider from between the lapping elements TI and I8 and the spider may be refilled progressively with work to be lapped.

Although but several specific. embodiments of the invention are herein shown and described, it

will be understood that various changes in the size, shape and arrangement of parts may be made without departing from the spirit of my invention.

What I claim is:

1. flapping apparatus comprising a base structure, a carriage rotatably mounted on said base structure, means for supporting work including a work table rotatably mounted on said carriage in eccentric relationship with respect to the axis of said carriage and including a member for holding articles supported thereon against translatory movement with respect to said base structure, a lapping element on the work supporting face of said work table, means for simultaneously drivingly rotating said work table about the rotative axis thereof and revolving the same about the axis of said carriage, a lapping tool carrier rotatably mounted on said base structure, a lapping tool rotatably mounted on said tool carrier in eqcentric relationship with respect to the axis of the latter and having a lapping element thereon disposed in opposing relationship with respect to the lapping element of said work table, and

means for simultaneously drivingly rotating said tool about its rotative axis and revolving the same about the axis of said tool carrier.

2.; Apparatus for finishing peripheral surfaces of work having portions of circular cross section comprising a base structure, a carriage rotatably mounted on said base structure, means for supporting work including a work table rotatably mounted on said carriage in eccentric relationship with respect to the axis of said carriage, an

abrading element on the work supporting face of said work table, means for simultaneously drivingly rotating said work table about the rotative axis thereof and revolving the same about the axis of said carriage, a finishing tool having an abradlng element thereon disposed in opposing relationship with respect to said work table and adapted to operate upon peripheral surfaces of work disposed between it and said abrading element of said work table, and a member disposed between said abrading elements for holding pieces of work against *translatory movement with respect to said base structure while accommodating rolling of said peripheral surfaces between said abrading elements.

3. Lapping apparatus comprising a base structure, means mounted on said base structure for supporting work including a work table having a lapping element thereon anda member for holding the periphery of apiece of work in rotative contact with said element and against translatory movement relative to said base structure, a-

lapping tool carrier rotatably mounted on said base structure, a lapping tool rotatably-mounted on said tool carrier in eccentric relationship with respect to the axis of the latter'and having a lapping element thereon disposed in opposing rela tionship with respect to the lapping element of said work .table, and means for-simultaneously '15 and revolving the sameabout the axis oi..said

drivingly rotating said tool about its rotative-axis tool carrier.

4. Lapping apparatus comprising a base structure, means rotatably mounted .on said base structure for supporting workincluding a rotatable work table having. a lapping element there,- on and-a member for holding the-periphery of a interposed between said lapping elements normally spaced therefrom for holding peripheral portions of pieces of work in rotative contact with said lapping elements and against movement in unison therewith. 4

7. Lapping apparatus comprising a base structu're, a Journal member rotatably mounted on said basestructure, a support shiftably mounted on base-structure for 'reciprocatory movemerit ,toward and away from said journal melber, a second journal memberrotatably mounted 131m saidxshiitable'support, 'a spindle rotatably piece of work'in rotative contact with said element and against translator-y movement relative to said base structure, said member being adapts ed to accommodate rotationof said work about one of its axes, means for drivingly rotating said work table, a lapping tool carrier rotatably-f mounted on said base structure, a lapping tool rotatably mounted onsaid tool carrier in eccentric relationship with respect to the axis of the latter and having a lapping element thereon disposed in opposing relationship with respect to the lapping element of said work table, and.

means for simultaneously drivingly rotating said mounted in each journal having a rotative axis eccentric with respect to the latter, lapping elementson said spindles in opposed facing relationship with .respectto eachlothenmeans for drivingly rotating saidspindles and the lapping elements thereon in respectively opposite directlons' about.their axes, means for drivingly rotating saidJournals about their axes, and a spider disposed between said lapping elements having a plurality of slots therein for holding a plurality of pieces of .work in rolling lapping engagement with said lapping elements.

tool about its rotative axis and revolving the same about the axis of said tool carrier.

5. Apparatus for lapping peripheral portions of pieces of work comprising a base structure, means rotatably mounted on said base structure for supporting work including a rotatable work table, a lapping element on the work supporting face of said work table, means for drivingly rotating said work table, a lapping tool carrier rotatably mounted on said base structure, a lapping tool totatably mounted on said tool carrier'in eccentric 8. Lapping apparatus comprising a base structure, a journal member rotatably mounted on said base structure, a support shiftably mounted on said basestructure for reciprocatory movement toward and away from said journal member, a second journal member rotatably mounted on said shiitable support, a spindle rotatably mounted.-in each journal having a rotative axis eccentric with respect to the latter, lapping elements on said spindles in opposed facing relationship 1 with respect to each other, means for.

, independently rotating said journals with respect relationship with respect to the axis of the latter V and having a lapping element thereon disposed in opposing relationship with. respect to the lapping element of said work table, means for simulta- "to their rotative axes and'said spindles with respect to their rotative axes respectively, means for holding a plurality of pieces of work in a spaced arrangement between said lapping elements, and-apparatus for predetermining the fforce of application of said lapping elements to neously drivingly rotating said tool about its rotative axis and revolving the same about the axis of said tool carrier, and a member for.holding said peripheral portions of said work against translatory movement relative to said lapping elements while accommodating rotative move-J ment thereof.

6. Lapping apparatus comprising a base structure, a journal member rotatably mounted and said base structure, a supportshiftably mountedon said base structure for reciprocatory movement toward and away from said journal memher, a second journal member rotatably mounted on said shiftable support a spindle rot'atably said work- 9. In a lapping machine having a base, opposed "rotatable lapping elements and a work cage therebetween, a pair of rotatable spindles to support said elements, means simultaneously and positively to rotate said spindles in opposite directions a pair of aligned rotatable sleeves rotably supported in said base, eccentric bearing supports'in said sleeves for said spindles, and

'drivingmeanssimultanecusly and positively to rotate said sleeves to impart a planetary movement to eachfof said spindles and elements simultaneously'and uniformly to lap the opposite faces of a plurality of work pieces.

1 DAVID A. WALLACE. 

